Black Phosphorus Quantum Dot-Sensitized TiO₂ Nanotube Arrays with Enriched Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

Abstract

Photon absorption, charge separation and transportation, and charge-induced reactions at the active sites are the main crucial factors involved in the photoelectrochemical (PEC) water splitting. Herein, a combination of black phosphorus quantum dot (BPQD) sensitization and defect engineering strategies is employed to optimize the PEC performance of one-dimensional TiO2 nanotube array (NTA) photoanodes. The as-prepared TiO2–x /BP electrode exhibits a strong photocurrent density under simulated solar light irradiation, which is almost ∼3 times higher than that of bare TiO2. Specifically, the photocurrent increment of TiO2–x /BP is even larger than the sum of TiO2–x and TiO2/BP, verifying the synergistic effect of oxygen vacancies and BPQD sensitization. The maximum photoconversion efficiency of TiO2–x /BP is as high as 0.35%, while the value of TiO2 NTAs is calculated to be 0.13%. The results reveal that oxygen vacancies and BPQDs in the TiO2–x /BP composite not only facilitate the charge separation and transportation but also enhance the activity and quantity of reactive sites for water oxidation. The present strategy might open new routes to develop high-performance photoelectrodes for water splitting.

Controllable synthesis of Co nanoparticles with the assistance of cucurbit[6]uril and its efficient photoelectrochemical catalysis in water splitting on a g-C3N4 photoanode

“…4b). [30][31][32] As expected, g-C 3 N 4 /Q[6]-Co NPs possessed a maximum photoconversion efficiency (0.0242%), which was 12.6 times and 2.3 times higher than the values of bare g-C 3 N 4 (0.00193%) and Q [6]-Co NPs (0.0104%), respectively. The higher peak ABPE value indicated that the metal/semiconductor system could The band properties and semiconductor types were determined using the Mott-Schottky (M-S) diagrams based on the electrochemical impedance-potential measurements.…”

Aqueous Affinity and Interfacial Dynamics of Anisotropic Buckled Black Phosphorous

“…After the revelation in monoatomic single-layered form phosphorene, − it gained significance owing to its optoelectronic properties, − high charge-carrier mobility, , and ability to be exfoliated with different thicknesses ranging between 3 and 40 nm. Hence, a set of band gaps from 0.3–2.0 eV is observed depending on thickness. , BP finds its applications in several fields, such as surface electrocatalysis , and photocatalysis, − for its tunable band gap. As the application of BP involves several aqueous-phase systems, it is essential to understand the interaction of water molecules with the surface of BP.…”

Recent progress on post-synthetic treatments of photoelectrodes for photoelectrochemical water splitting

“…Firstly, NaBH 4 treatment could conveniently create oxygen vacancies (O vac ) in photoelectrodes. 37,38 Zheng et al reported that O vac could be introduced in black phosphorus (BP)-modied TiO 2 photoanodes by soaking them in a NaBH 4 aqueous solution. 37 The synergistic effect of O vac and BP quantum dot sensitization was veried by PEC measurements.…”

“…37,38 Zheng et al reported that O vac could be introduced in black phosphorus (BP)-modied TiO 2 photoanodes by soaking them in a NaBH 4 aqueous solution. 37 The synergistic effect of O vac and BP quantum dot sensitization was veried by PEC measurements. Notably, the generated O vac and BP sensitization could not only facilitate charge separation but also enhance the water oxidation reaction, by improving the activity and quantity of reactive sites.…”